diff --git a/emacs/init.org b/emacs/init.org
index 3aaf0d3..9dd2fea 100755
--- a/emacs/init.org
+++ b/emacs/init.org
@@ -1354,6 +1354,17 @@ A function to run a pipenv-aware python repl:
     (run-python nil nil t))
 #+END_SRC
 
+Run black on the current buffer:
+#+BEGIN_SRC emacs-lisp
+  (defun blacken ()
+    (interactive)
+    (let ((start (if (use-region-p) (region-beginning) (point-min)))
+	  (end (if (use-region-p) (region-end) (point-max))))
+      (shell-command-on-region start end "black -q -" nil t)))
+
+  (general-def 'normal python-mode-map "C-M-\\" #'blacken)
+#+END_SRC
+
 * Hy
 Python but Lispy!